What’s Coming To Concrete Pavements
Jason Weiss, wjweiss@purdue.edu, Purdue University
Jack and Kay Hockema Professor & Director of the Pankow Materials Laboratory
A Century of Change
re 1936 I-465 2002
The Century Has Seen Mass Production and Increased Automation in Concrete as Well
Comment on Testing
Moore 1936 PCA 2002
ASTM D138-32T
Tentative Method of Test
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Every Day Is About Survival
• Every morning in Africa, a zebra wakes up. It knows it must run faster than the fastest lion or it will be killed. Every
morning a lion wakes up. It knows it must outrun the slowest zebra or it will starve to death. It doesn’t matter
whether you are a lion or a zebra:
when the sun
comes up, you’d better be running
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Take Advantage of Technology
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Innovative New Tests
• Much like Indiana we seem to be on the impossible
search for the
“holy grail”
• We want a test for
transport (or durability) that is fast,
accurate, inexpensive easy to interpret but it also needs to be scientifically valid
• We think that electrical measurements can be a significant part of this approach
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Uniaxial Resistivity
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S
Pore
f
Bulk
σBulk: concrete conductivity (S/m)
σPore: pore solution conductivity (S/m)
: pore volume volume fraction
: avg. liquid connectivity (describes liquid tortuosity and constrictedness) S: Degree of Saturation (typ. Ignored)
Electrical Properties
• Considers pore fluid as the only conductive phase
• Pore fluid (capillary, gel pores)
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Transport in Large Pores
• Transport mainly in capillary pores
• Capillary pores are large and connected
• SCM are important
• W/C and Curing:
Influence Capillary Porosity
Capillary Pores
Lower w/c Higher w/c
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Prescriptive Specifications and Cookies
• Think specifications (HPC)
• Ruth Graves Wakefield (1930) changed cooking in america with specifications
• Tollhouse came up with an easy way to get consistent cookies
• What about Grandma though
• HPC due to experience and innovation
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Slow Movement to Performance
• Late 90’s work on implementing PRS
• Still an area of active
research with hard questions
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Performance Specifications
• Active area of research
• Opportunities in models,
tests, targets, variability
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Recipe versus Performance
• While recipes have their place there is room for innovation and performance
based on the overall performance of the system – let the chef innovate
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Cement and CO
2Production
Ordinary Portland Cement Manufacturing
Portland Limestone
Cement Manufacturing
Approach for Manufacture of Portland Limestone Cement Similar performance
s targeted
PLC is generally
ground finer than OPC
– PLC requires more grinding – Higher fineness may act as
a nucleating agent to increase early age strengths
Higher reaction rates may show benefits of blending with other supplementary materials
Finer Cement
Less Clinker
Time f’c
28 d
A Technology Ready To Implement
• adfsf
0 4000 8000 12000
OPC Compressive Strength (psi) 0
4000 8000 12000
PLC Compressive Strength (psi) w/p = 0.38 w/p = 0.42 w/p = 0.46
nyone Notice ts Cold this
Year ?
s 2008
Taylor 2013 Weiss 2005
Taylor 2013
Salts Increase Saturation
Taylor 2013
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Comments on Salts
0.6 0.4 0.2 0.0 -0.2
e of Water Loss water / mm2 of surface)
DI Water MgCl2 0.9%
Water Salt Solution
Fixed RH Atmosphere
40 60 80 100
RH (%)
• Freezing temp
• Viscosity
• Water Activity (Equilibrium RH)
• Dry/Wet DOS
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What Does Internal Curing Do
• The goal of internal curing is to provide
reservoirs of water for curing low w/c, hpc to minimize the potential for cracking and to
realize high performance mixtures
1) Improved Corrosion Resistance - Durability 2) Reduced Cracking
3) Reduces Curl
• Goal (specification)
– High durability
– Low permeability
– Low cracking potential
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Determining Free Water
Paper Towel Method
Centrifuge Method
• The goal is to get the aggregate to a prewetted surface dry condition
• One can weigh the aggregate, spread it out and dry it slowly till the surface has no water – Paper
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Service Life Prediction
INDOT Class C; NYDOT IC HPC
• Here we see the predicted service life model results for the decks cast in 2010
• Class C concrete 20 yrs, ICHPC 55-90 yr
• Model assumes no cracks
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Quality Control Wagon
• An opportunity to help improve the quality of concrete emphasizing
‘the basics’ of good concrete technology/
tracking performance
• Education and training opportunity
• Mobile lab to transfer knowledge to the field (deck/sidewalk/curb) and assess the performance of new approaches
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MIMTL Moving Forward
• Mobile Infrastructure Materials Testing Laboratory (MIMTL)
– Resistivity as a Quality Control Method – Looking at Quality Control PRS
– Deicers/Sealers – Internal Curing – Indiana as
a Classroom – Tracking
long term
– New Maturity
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